title: Long-distance axonal transport of AAV9 is driven by dynein and kinesin-2 and is trafficked in a highly motile Rab7-positive compartment.
abstract: Adeno-associated virus (AAV) vectors can move along axonal pathways after brain injection, resulting in transduction of distal brain regions. This can enhance the spread of therapeutic gene transfer and improve treatment of neurogenetic disorders that require global correction. To better understand the underlying cellular mechanisms that drive AAV trafficking in neurons, we investigated the axonal transport of dye-conjugated AAV9, utilizing microfluidic primary neuron cultures that isolate cell bodies from axon termini and permit independent analysis of retrograde and anterograde axonal transport. After entry, AAV was trafficked into nonmotile early and recycling endosomes, exocytic vesicles, and a retrograde-directed late endosome/lysosome compartment. Rab7-positive late endosomes/lysosomes that contained AAV were highly motile, exhibiting faster retrograde velocities and less pausing than Rab7-positive endosomes without virus. Inhibitor experiments indicated that the retrograde transport of AAV within these endosomes is driven by cytoplasmic dynein and requires Rab7 function, whereas anterograde transport of AAV is driven by kinesin-2 and exhibits unusually rapid velocities. Furthermore, increasing AAV9 uptake by neuraminidase treatment significantly enhanced virus transport in both directions. These findings provide novel insights into AAV trafficking within neurons, which should enhance progress toward the utilization of AAV for improved distribution of transgene delivery within the brain.
authors.affiliation: Research Institute of the Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; W.F. Goodman Center for Comparative Medical Genetics, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA; Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Castle
authors.affiliation: Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA; Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel.
authors.forename: Eran
authors.initials: E
authors.lastname: Perlson
authors.affiliation: Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Erika Lf
authors.initials: EL
authors.lastname: Holzbaur
authors.affiliation: Research Institute of the Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; W.F. Goodman Center for Comparative Medical Genetics, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA; Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA. Electronic address: jhwolfe@vet.upenn.edu.
authors.forename: John H
authors.initials: JH
authors.lastname: Wolfe
mesh_terms: D000818:Animals; D001370:Axonal Transport; D002478:Cells, Cultured; D000229:Dependovirus / Q000502:physiology*; D004398:Dyneins / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism; D016547:Kinesins / Q000378:metabolism*; D009439:Neuraminidase / Q000494:pharmacology; D009474:Neurons / Q000378:metabolism / Q000821:virology*; D051381:Rats; D020691:rab GTP-Binding Proteins / Q000378:metabolism*; D000090802:rab7 GTP-Binding Proteins
chemical_list: D000090802:rab7 GTP-Binding Proteins; C000716466:rab7 GTP-binding proteins, rat; D009439:Neuraminidase; D004398:Dyneins; D016547:Kinesins; D020691:rab GTP-Binding Proteins